Washing machine including integral filter module

ABSTRACT

A washing machine comprising: i) a wash tub ( 12 ), ii) a water inlet ( 14 ) and waste water outlet ( 16 ) in fluid communication with the wash tub ( 12 ), iii) a fluid pathway ( 18 ) extending from the waste water outlet ( 16 ) to the water inlet ( 14 ), iv) a pump ( 20 ) for moving water along the fluid pathway ( 18 ), v) a filter module ( 22 ) located along the fluid pathway ( 18 ), and vi) a valve ( 16′ ) located downstream from the pump ( 20 ) that selectively directs fluid flow along the fluid pathway ( 18 ) to a waste discharge port ( 28 ) or the filter module ( 22 ).

FIELD

The present invention is directed toward washing machines for washinglaundry or “ware” items such glassware, tableware, flatware, dishware,cookware and the like.

INTRODUCTION

Washing machines for cleaning laundry and ware items are well known inthe art. A typical washing machine includes a wash tub and anelectrically operated pump which are housed in a cabinet. The tub isaccessible by way of a sealable door. During a typical wash cycle, waterand detergent are combined and manipulated about the wash tub during awashing stage, after which time the resulting waste water is discharged.The tub is subsequently refilled with fresh feed water in one or morerinse stages. The repetitive filling and draining of the wash tub takestime and uses a large quantity of water.

SUMMARY

In a primary embodiment, the present invention reduces water consumptionand refilling time associated with washing laundry and ware items. Theinvention includes a washing machine comprising:

-   -   i) a wash tub (12),    -   ii) a water inlet (14) and waste water outlet (16) in fluid        communication with the wash tub,    -   iii) a fluid pathway (18) extending from the waste water outlet        (16) to the water inlet (14),    -   iv) a pump (20) for moving water along the fluid pathway (18),    -   v) a filter module (22) located along the fluid pathway (18),        and    -   vi) a valve (16′) located downstream from the pump (20) that        selectively directs fluid flow along the fluid pathway (18) to a        waste discharge port (28) or the filter module (22). In another        embodiment, the invention includes a method for cleaning items        using such a washing machine, including: a) initiating a wash        stage by introducing water and detergent into the wash tub        (12), b) actuating the valve (16′) to direct waste water        resulting from the wash stage to the waste discharge port        (28), c) initiating a rinse stage by introducing water without        detergent into the wash tub (12), d) actuating the valve (16′)        to direct at least a portion of the waste water resulting from        the rinse stage to the filter module (22), and e) reintroducing        waste water which has passed through the filter module (22) into        the wash tub (12).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic view of an embodiment of a washing machine accordingto the present invention.

DETAILED DESCRIPTION

As used herein, the term “ware” refers to items such as glassware (e.g.bottles), tableware, flatware (e.g. cutlery, utensils), dishware (e.g.dishes), cookware, (e.g. pots, pans) and other items for use with foodand beverages during their preparation, storage or consumption. The term“laundry” refers to items made from textiles or fabrics including itemssuch as clothing and linens (e.g. tablecloths, bedding, towels, etc.).In one embodiment, the invention includes a washing machine designed toclean ware items. In another embodiment, the invention includes awashing machine designed to clean laundry items. In yet anotherembodiment, the invention includes a personal bathing assembly, e.g. tubor shower.

A schematic view of a generic embodiment of the invention is provided inFIG. 1 wherein a washing machine is generally shown at 10 including awash tub (12) adapted to temporarily house items to be cleaned. Whilenot particularly limited, the wash tub (12) preferably includes asealable door that provides convenient access to an inner chamber. In anembodiment designed to clean ware items, the wash tub (12) may includeshelves and compartments for securing ware items during cleaning. In anembodiment designed to clean laundry, the wash tub (12) may includecylindrical drum which is capable of spinning about an axis. The washtub (12) is in fluid communication with at least one water inlet (14)and a waste water outlet (16). The water inlet (14) is adapted toprovide a route for liquid to flow into the wash tub (12) while thewaste water outlet (16) provides a route for waste water to flow out ofthe tub (12). For purposes of this description, the term “waste water”refers to water that has been used to either wash or rinse items withinthe tub (12).

The inlet (14) and outlet (16) are preferably connected to one or morevalves (14′, 16′) that selectively control ingress and egress of liquidinto and out of the tub (12). A fluid pathway (18) comprising one ormore pipes (e.g. tubes, conduits, etc.) extending from the waste wateroutlet (16) to the water inlet (14). A pump (20) provides a drivingforce for moving water along the fluid pathway (18). As will bedescribed below, one or more pumps may be utilized but in a preferredembodiment, a single pump is utilized.

A filter module (22) is located along the fluid pathway (18). The filtermodule (22) may include a wide variety of separation mediums includingmembrane-based modules (e.g. spiral wound, hollow fiber, capillary, flatdisks, and tubular membrane modules or “elements”). Representativesemi-permeable membranes include those made from: various ceramics,metals, celluloses, polysulfones, polyether sulfones, polyvinylidenefluoride, polyamides, polyacrylonitrile, polyolefins, etc. The membranesmay be suitable in a wide range of applications including but notlimited to microfiltration (MF), ultrafiltration (UF), nanofiltration(NF) and reverse osmosis (RO). In preferred embodiments, the moduleincludes a plurality of semi-permeable membranes located within an innerchamber of a housing. The average pore size of the hollow fibermembranes utilized within the filter module (22) may be selected so asto preferentially remove debris such as food, grease, proteins, oils andthe like, e.g. average pore sizes in the microfiltration range (i.e. 0.1to 5 micron). In a preferred embodiment, the average pore size of themembrane is in ultrafiltration range, (i.e. 0.01 to 0.10 micron) suchthat protozoa, bacteria and viruses are at least partially removed. Inone embodiment, a plurality of semi-permeable hollow fiber membranes areorientated axially within an inner chamber. The ends of the hollowfibers are sealed from the inner chamber by way of well known “potting”techniques wherein one or both ends of the hollow fibers remain open andin fluid communication one or more outer chambers formed within an endcap assembly. In a preferred embodiment, the filter module (22)comprises an elongated-shaped housing, (e.g. an elongated shell having alength greater than its width), extending along an axis between twoopposing ends and defining an inner chamber. The outer periphery of thefilter module is cylindrically-shaped having a circular cross-section.The housing may be constructed from a wide variety of materials, e.g.plastics, ceramics, metals, etc., however, in one set of preferredembodiments the housing is made from an injection moldable plastic suchas polyvinyl chloride (PVC) or acrylonitrile butadiene styrene (ABS).Representative examples include miniaturized versions of Dow™ UF modulesSFX 2660 and SFX 2680. While shown as a single unit, multiple filtermodules may be used in a parallel or serial arrangement. Multiple filtermodules may be of the same or different filtration sizes (e.g. MF andUF). Multiple filter modules may be of the same or different outerand/or inner structure.

The washing machine (10) optionally includes an aerator (24) in fluidcommunication with the filter module (22). The aerator provides a sourceof gas bubbles (e.g. air bubbles) to the inner chamber of the filtermodule which remove debris from the surface of membrane. In oneembodiment, the aerator comprises one or more gas nozzles in fluidcommunication with a source of gas such as ambient air. Gas pressure maybe generated by an independent pump or gas blower (not shown).Alternatively, gas bubbles may be generated using the same pump (20)used to move water along the fluid path (18). For example, the aerator(24) may include a valve positioned along the fluid pathway (18) whichselectively opens to permit air to be drawn into the fluid pathway aswater passes through the pathway, i.e. via a Venturi effect. While notshown, the aerator may also be in direct fluid communication with thewash tub (12) to provide gas bubbles to the tub during cleaning or rinsestages.

The washing machine includes a feed water port (26) adapted forconnection to a source of water (e.g. tap water), a waste discharge port(28) adapted for connection with an external drain, and a filterdischarge port (30) adapted to an external drain. The waste dischargeport (28) and filter discharge port (30) may be combined into a singleport. Each port may include a valve which may be selectively opened orclosed during operation. In addition, a valve (not shown) may be locatedbetween the waste water outlet (16) and the pump (20) to drain wastewater from the wash tub (12).

The valve (16′) is located downstream from the pump (20). In a preferredembodiment, the valve (16′) is located upstream of the filter module(22), i.e. along the fluid pathway (18) between the pump (20) and filtermodule (22) as illustrated in FIG. 1. The valve (16′) selectivelydirects fluid flow along the fluid pathway (18) to the waste dischargeport (28) located downstream of the pump (20), or to the filter module(22). Optionally, the valve (16′) may be selected from the group of amulti-way valve, a single valve, and a number of valves functioning witheach other. The valve (16′) and the valves nearby may be positionedseparated or in a common support plate or integrated into the end cap ofthe filter module (22). Valve (16′) is preferably a three-way valve thatmay be actuated by way of an electronic controller.

In a preferred embodiment the aforementioned components of washingmachine (10) are integrally housed within a cabinet (32). In a preferredcommercial embodiment, the filter module (22) is relatively small insize as compared with the washing machine, e.g. the volume ratio of thefilter module (22) to the cabinet (32) is preferably from 1:20 to1:1000.

The invention further includes a method of cleaning items using thewashing machine as previously described. In a preferred embodiment, themethod includes loading items to be washed within the wash tub andperforming the following steps: a) initiating a wash stage byintroducing water and detergent into the wash tub (12), b) actuating thevalve (16′) to direct waste water resulting from the wash stage to thewaste discharge port (28), c) initiating a rinse stage by introducingwater without detergent into the wash tub (12), d) optionally directinga portion of waste water resulting from the rinse stage to the dischargeport (28), e) actuating the valve (16′) to direct at least a portion ofthe waste water resulting from the rinse stage to the filter module(22), and f) reintroducing waste water which has passed through thefilter module (22) (i.e. filtered water or “permeate”) into the washtub. The step of reintroducing such filtered water may include the useof such water in the same rinse stage, or a subsequent rinse stage, orin a subsequent wash cycle wherein detergent and optionally fresh waterare combined. So called “wash stages” are characterized by thecombination of water with a detergent or other cleaning compositionwhereas rinse stages generally include no detergent (althoughanti-scalants may be used).

By way of example, in operation items to be cleaned are positionedwithin the wash tub (12) and feed water selectively enters the wash tub(12) by way the feed water port (26). Automated valves and a pump mayfacilitate this process so that an optimized water level is achieved.Detergent or other cleaning compounds also may also be provided and theresulting wash water is sprayed, agitated or otherwise manipulated aboutthe tub (12) to remove debris from the items. Thereafter, i.e. typically10 to 30 minutes, the wash stage ends and the resulting waste water isdrained from the tub (12) by way of the waste water outlet (16). Onceagain, automated valves and the pump (20) may facilitate this process.The waste water is removed from the washing machine (10) by actuatingthe valve (16′) to direct waste water resulting from the wash stage tothe waste discharge port (28).

After the wash stage one or more rinse stages are initiated. Watercomprising feed water from the feed water port (26) or permeate passingthrough the membrane of the filter module (22), or a combination of bothwater sources is used as rinse water and is introduced into the wash tub(12) through water inlet (14). A preferred mix ratio is at least 3:1permeate to fresh feed water. When operated in cross-flow mode,concentrated waste water unable to pass through the membranes may bedischarged by way of the filter discharge port (30). When operating indead end flow mode, debris is collected within the module (22), whichmay be replaced on a periodic basis. In a preferred embodiment, wastewater from the wash stage is disposed of via the waste discharge port(28), but waste water from the first rinse stage is recycled through thefilter module (22) and reused.

The membrane may be cleaned by introducing gas bubbles into the filtermodule (22) by way of the aerator (24). Bubbles flow upward through themodule (22) and dislodge debris that collects upon the surface of themembrane. The bubbles may then selectively exit the module (22) by wayof filter discharge port (30) (e.g. preferably a port located at theupper portion of the module (not shown)). Additionally, feed water maybe periodically back-flushed through the membrane and removed from themodule (22) by way of the waste discharge port (28) or the filterdischarge port (30). Aeration may be conducted after a wash or rinsestage, or may be continuous throughout one or more stages, or may becyclic/intermittent/pulsed throughout one or more stages, or may beconducted both throughout and after one or more stages. Similarly,filtration of waste water may occur continuously through a wash or rinsestages, or be conducted off-line and stored within an interior orexterior holding tank for use in subsequent wash or rinse stage. In apreferred embodiment, filtration occurs continuously during the firstrinse stage. Integrated circuitry or similar means may be used tocontrol stage timing and value actuation during the cycle.

In addition to wash and rinse stages, integrated circuitry may besuitable to implement a separate cleaning stage. In this cleaning stage,aeration may be performed without permeation through the module (22).Alternatively, the cleaning stage may also include aeration and backwash(reverse permeation from normal operation) and/or forward wash fromthrough the module (22). For instance, this may be implemented byredirecting a valve to provide pressurized water from the feed waterport (26), the wash tub (12) or pump (20) to the module's inner chamber.This cleaning stage may include continuous or batch removal of debrisfrom the module (22) through the waste discharge port (28) or thedischarge port (30). The cycle time for the cleaning stage may be longerthan for either the wash or rinse stages. Optionally, the cleaning stagemay further include chemical soaking and cleaning by introducingchemicals into the module (22).

The following is a non-limited example of this invention. It should beunderstood that the total reduced water consumption calculated in theexample depends upon the water consumed during individual stages andshould not be treated as limitation of the invention.

EXAMPLES Example 1

A washing machine (8 kg wash tub capacity) as configured in FIG. 1 maybe operated with a wash stage followed by two sequential rinse stageswith each stage utilizing approximately 20 liters of water. Waste waterassociated with the wash stage is discharged via the water dischargeport. Waste water associated with the first rinse stage is continuouslyfiltered through a filtration module (UF hollow fiber) operating indead-end mode. The resulting permeate is combined with fresh feed waterand reused for the second rinse stage. A preferred mix ratio is at least3:1 permeate to fresh feed water. Aeration of the filter module ispreferably conducted during the rinse stage. This embodiment of theinvention reduces total water consumption by approximately ⅓ per cycleand further reduces the total time of the cycle. The filter module (22)removes debris, bacteria and viruses from the waste water so that theitems in the wash tub (12) do not become soiled or contaminated.

What is claimed is:
 1. A washing machine comprising the followingcomponents: i) a wash tub (12), ii) a water inlet (14) and waste wateroutlet (16) in fluid communication with the wash tub, iii) a fluidpathway (18) extending from the waste water outlet (16) to the waterinlet (14), iv) a pump (20) for moving water along the fluid pathway(18), v) a filter module (22) located along the fluid pathway (18), andvi) a valve (16′) located downstream from the pump (20) that selectivelydirects fluid flow along the fluid pathway (18) to a waste dischargeport (28) or the filter module (22).
 2. The washing machine of claim 1further characterized by including a single pump (20).
 3. The washingmachine of claim 1 further characterized by including a single valve(16′) located along the fluid pathway (18) between the pump (20) and thefilter module (22).
 4. The washing machine of claim 1 furthercharacterized by including a single valve (16′) located along the fluidpathway (18′) between the wash tub (12) and the filter module (22).
 5. Amethod for washing ware or laundry items using a washing machinecomprising the following components: i) a wash tub (12), ii) a waterinlet (14) and waste water outlet (16) in fluid communication with thewash tub, iii) a fluid pathway (18) extending from the waste wateroutlet (16) to the water inlet (14), iv) a pump (20) for moving wateralong the fluid pathway (18), v) a filter module (22) located along thefluid pathway (18), and vi) a valve (16′) located downstream from thepump (20) that selectively directs fluid flow along the fluid pathway(18) to a waste discharge port (28) or the filter module (22); whereinthe method comprises: a) initiating a wash stage by introducing waterand detergent into the wash tub (12), b) actuating the valve (16′) todirect waste water resulting from the wash stage to the waste dischargeport (28), c) initiating a rinse stage by introducing water withoutdetergent into the wash tub (12), d) actuating the valve (16′) to directat least a portion of waste water resulting from the rinse stage to thefilter module (22), and e) reintroducing at least a portion of wastewater which has passed through the filter module (22) into the wash tub(12).